DE19549097A1 - Semiconductor package for surface mounting - Google Patents

Description

The present invention relates to a semiconductor package for surface mounting and especially, but not from finally, on a power control semiconductor device that so is designed to be used by surfaces mounting on a printed circuit board or a circuit board can be fastened, which consists of an insulating metal substrate (IMS).

A typical semiconductor package for surface mounting includes a semiconductor device that is molded in an art existing material material is embedded. On off Metal existing lead frame, which is also partially in is embedded in the body, connects the semiconductor device electrically with connecting pins extending outwards, the one with a trace on a circuit board or a isolated metal substrate are soldered.

A typical example of a known semiconductor package is shown in section in FIG. 1. As can be seen, the component comprises a plastic material body 2 with a verti cal end face 4 , from the center of which the connecting pins 6 (one of which is shown in the drawing) occur. The terminal pins have a flat upper section 8 , a downwardly angled section 10 and an outer lower and flat section 12 . Outer portion 12 is attached to substrate 14 , typically a printed circuit board or an insulated metal substrate, by soldering (not shown).

A problem with this known type of semiconductor device is that it can be difficult to manufacture the pins 6 so as to ensure that the outer portion 12 is flat and makes good contact with the substrate. For example, if the pins are only slightly bent or if they are not manufactured with acceptable accuracy, the electrical contact may be unreliable.

The invention has for its object a semiconductor package to create the type mentioned, in which this difficult speeds are reduced and with relatively little effort Production is easily attachable to a suitable substrate.

According to a first basic concept of the invention, a semi-conductor housing for surface mounting is provided which has a semiconductor component molded into a body 10 made of plastic material, two input electrodes 12 , 14 for controlling the semiconductor component and an output electrode 16 ; 18 for supplying an output signal from the semiconductor component, the input and output electrodes extending out of the body and the semiconductor housing being characterized in that the input electrodes are offset from one another.

According to a further basic idea of the invention, a semi-conductor housing for surface mounting is created, which has a semiconductor component molded into a body 10 made of plastic material, two input electrodes 12 , 14 for controlling the component and an output electrode 16 ; 18 for providing an output signal from the semiconductor device, the input and output electrodes extending out of the body and the semiconductor package being characterized in that the body has a channel 22 ; 24 includes, wherein the lower surface when using the semiconductor package is arranged so that it contacts a mounting substrate 33 .

According to a third basic concept of the present invention, a semiconductor housing for surface mounting is created which comprises a semiconductor component molded into a body 10 made of plastic material, two input electrodes 12 , 14 for controlling the component and an output electrode 16 ; 18 for supplying an output signal from the semiconductor component, wherein the input and output electrodes extend out of the body and the semiconductor housing is characterized in that the output electrode comprises a connection pad 16 ; 18 , which is formed when using the semiconductor package so that it contacts a conductive portion 38 of a mounting substrate 33 , wherein the terminal pad is deformed in steps by partial shear.

The input electrodes preferably comprise elongated ones Pins that come from a general level of the housing are bent out. The pins that ver against each other can initially be part of a flat blank (preferably with a constant thickness), the Pins bent into position during manufacture will. Alternatively, the connector pins can simply be cut off when they are not needed.

According to a preferred embodiment, the connection pins arranged generally parallel in the blank and they overlap each other. The points at which the Pass the pins into the remaining part of the blank, adjacent to the outer edges of the blank. By use formation of overlapping connection formed in this way donate, preferably in the transverse direction over the blank material is saved because there is no need exists, the blank only for this reason excessively long make so that there is enough material from which the connection pens can be made.

The connection pins preferably form input (signal) Electrodes on the semiconductor component, or the input electrodes could alternatively include connection pads. It can be a or multiple output (power) electrodes may be provided, the preferably in the form of terminal pads, which at their application are arranged so that they are electrically conductive portion of a substrate can be attached  for example on a printed circuit board or an insulated one Metal substrate. Alternatively, the output electrodes can also be used have the shape of pins.

The body of the semiconductor package is preferably made of one Plastic material molded, which makes the semiconductor device is encapsulated. Can in a lower surface of the body a channel can be formed. When using the semiconductor this channel forms a through opening between the housing the lower surface of the body and the mounting substrate, through which washing solutions can be passed. It is further preferably provided that the channel arranged so is that it is part of an electrical leakage current path along the bottom surface of the body. Example the channel between the output electrode or the Output electrodes and a heat sink may be arranged.

In the preferred embodiment, either include the On output electrodes or the output electrodes or both connection pillow that so when using the semiconductor package are arranged with a conductive portion of a loading mounting substrate are in contact. The connection pads are preferably partially deformed by shear. this makes possible the use of a single thickness blank either for the input electrodes or for the output electrodes tread or for both. With the scissors part of the lower one Surface of each terminal pad pressed down so that a downward contact surface is formed which is suitable for an electrical connection to the substrate.

In the body made of plastic material is located at least one semiconductor device (or a plurality of interconnected semiconductor components). For example the case could be both a diode and a transistor contain.

The invention further relates to a semiconductor package for surface mounting, one in one made of plastic  molded body made of material, two input electrodes for controlling the component and one Output electrode for supplying an output signal from the Semiconductor device comprises, wherein the input and output stick electrodes out of the body and being half conductor housing is characterized in that the input electrodes are located at one end of the body while the off is arranged at an opposite end. Such an arrangement reduces electrical interference problems (for example, disturbances caused by network disturbances).

The invention also extends to an arrangement of half conductor housings for surface mounting, each of which looks like this are formed, as described above. These Arrangement or group of semiconductor packages can under Ver application of the feature of displacement of the input electrodes are connected in parallel, one of the input electrodes each housing connected to a first signal trace while the other input electrode on each semiconductor Housing connected to a second parallel signal trace becomes. The first and second signal conductor tracks can be on a separate control circuit board, which, if this is desirable above the arrangement or group can be arranged. If the input electrodes are elongated Include pins, so these pins can extend up from the substrate and they can on the first and second conductor tracks of the control circuit board be attached.

In a preferred embodiment, openings in the Control circuit board may be provided through which the pins extend. The outer ends of the Terminal pins are then soldered to the conductor tracks or otherwise electrically connected.

The present invention further extends to Method of manufacturing a semiconductor package for the Surface mounting. It continues to extend to a ver  start to attach such a semiconductor package a substrate including the washing step of the semiconductor package. The invention also extends on the assembly of a group of such semiconductor packages.

The invention further extends to one or more the above-mentioned or described in the following description characteristics, either individually or in any given combination.

It is also possible that the semi-conductor according to the invention housing in some embodiments only an input (or signal) electrode instead of two electrodes.

Exemplary embodiments of the invention are described below the drawing explained in more detail.

Show in the drawing

Fig. 1 is a schematic sectional view of a conventional semiconductor package for surface mounting,

Fig. 2 are perspective views of a Halbleitergehäu ses for surface mounting according to a first aspect of the present invention,

3, the way how the semiconductor package of FIG. 2 can be mounted in parallel FIG.

Fig. 4 is a plan view of the embodiment of FIG. 2, prior to the bending of the connection pins of the lead frame

Fig. 5 shows the lead frame for the embodiment of Fig. 2,

Fig. 6 is a plan view of a second embodiment of the present invention,

Fig. 7, the lead frame of the embodiment of FIG. 6, and

Fig. 8 shows the way in which the shear under thrown parts of Fig. 6 are formed.

Fig. 2 shows a first embodiment of a semiconductor package for surface mounting according to the present invention. This housing comprises a molded plastic body 10 in which (in a manner not shown) a semiconductor component is embedded. In the specific example shown, the semiconductor component is a power control semiconductor component, to which control signals are supplied via two upward-pointing metallic connection pins 12 , 14 . The output power is supplied at the other end of the component via two metallic connection pads 16 , 18 . On the underside of the component there is a metal heat sink 20 , which is neither electrically connected to the connecting pins 12 , 14 nor to the connecting pads 16 , 18 or the embedded semiconductor component. On the underside of the body 10 between the cooling body 20 and the connecting pins 12 , 14 , a transverse groove 22 is formed, which has a central, forward-facing opening 28 . In a similar manner, a similar groove 24 is formed between the rear edge of the cooling body 20 and the connection pad 16 , 18 . The groove 24 has an opening 26 arranged in the middle and directed towards the rear, which opens into the space between the connection pads 16 , 18 .

When used, the semiconductor package is secured by surface mounting on a substrate, for example on a circuit board with printed conductor tracks or on an insulated metal substrate with conductor tracks, the heat sink 20 resting on a heat sink of the circuit board and the connection pad 16 , 18 with conductive tracks on the PCB are soldered. Control signals are the pins 12 , 14 supplied either by soldering wires directly to the upwardly projecting portions of the pins, or alternatively that the flat undersides of the pins 30 , 32 are soldered to the circuit board with suitable signal conductor tracks.

FIG. 3 shows how a multiplicity of the semiconductor packages according to FIG. 2 can be attached and used in parallel. In Fig. 3 two such semiconductor packages are shown when they are attached to a printed circuit board with an insulated metal substrate (IMS). The IMS circuit board 33 comprises a heat-conducting substrate 34 (for example on aluminum) which carries an electrically insulating surface 36 . Parallel conductor tracks 38 , 40 made of copper are located on the surface. The semiconductor housings or semiconductor components are fastened in such a way that the connection pads 16 , 18 are fastened to the conductor track 38 (for example by soldering), the heat sink 20 being fastened to the conductor track 40 .

Above the row of semiconductor packages or semiconductor components is a control circuit board 42 with two copper signal conductor tracks 44 , 46 . Openings in the circuit board allow the upright connector pins 12 , 14 to pass through the circuit board so that they come into contact with respective enlarged contact sections 48 , 50 of the conductor tracks 46 , 44 . Good electrical contact is ensured by soldering the enlarged areas and the connecting pins in a manner not shown.

It can be seen that the pins 12 , 14 are arranged in steps, thereby ensuring that all pins 12 are on a horizontal line, while all pins 14 are on another parallel horizontal line.

In operation, control signals are simultaneously delivered to all electronic components along the conductor tracks 44 , 46 . The output power occurs in the conductor track 38 on the IMS circuit board 33 . It has been stated above that the heat sinks 20 are electrically disconnected and the heat sinks are normally grounded through the copper trace 40 . Alternatively, in a modification of the embodiment, the heat sink 20 could represent one of the output power connections, the connection pads 17 , 18 forming the other connection. In a further modification (which would require a different arrangement of the copper conductor tracks on the IMS circuit board), the connection pad 16 could represent a first output power connection, while the connection pad 18 represents the other output power connection.

Because of the large voltages that can be generated on the conductor track 38 , it is important to ensure that no sparkovers or breakdowns occur between the conductor track 38 and the conductor track 40 . The groove 24 causes an improvement in the electrical insulation between the two conductors because it increases the electrical leakage current path along the lower surface of the body 10 made of plastic material. If the groove 24 were not present and the lower portion of the body were flat, the leakage path would be shorter, which would mean that a breakdown could occur at a lower voltage, especially if the surface is somewhat damp.

The semiconductor packages are normally attached to the IMS circuit board by first applying a mixture of flux and solder (solder paste) to the circuit board using the screen printing process. In this method, however, difficulties can arise due to the fact that a certain amount of residues remain on the circuit board. Furthermore, the solder paste can be squeezed from under the underside of the connection pads 16 , 18 . In known semiconductor packages which do not have a groove 24 , pressed-out solder paste can move very quickly over a large part of the distance between the conductor track 38 and the conductor track 40 . On the other hand, if the groove 24 is provided, excess solder paste is normally taken up in the channel formed by this groove. Once the semiconductor packages have been attached to the IMS circuit board, solder paste and residues can be removed by passing a washing liquid along the grooves 22 , 24 . The washing liquid also flows through the openings 26 , 28 ( Fig. 2), ensuring that all the areas around the terminal pads 16 , 18 and the lower portions 30 , 32 of the terminal pins are free of unwanted material.

FIG. 4 shows a plan view of the semiconductor housing according to FIG. 2 before the connection pins 12 , 14 have been bent upwards. As can be seen, in this manufacturing stage of the end product, the pins 12 , 14 in a one level, and they can be bent in the required manner to a shape that is determined by the end user. In some cases, the end user may prefer to route a signal over conductive traces on the IMS circuit board and connect to the semiconductor package via the lower portions 30 , 32 of the pins. In this case, the connector pins can simply be cut off.

The product shown in FIG. 4 is, to be more precise, a slight modification of the semiconductor package according to FIG. 2, because this semiconductor package has a cut-out area 56 in the rear edge of the body and a similar cut-out area 58 in the front edge. This enables wash solutions to enter channels 22 , 24 more easily.

Fig. 5 shows a previous stage of the manufacturing process, namely the lead frame which eventually forms the pins 12 , 14 and the pads 16 , 18 . The lead frame is formed by a flat metal stamped part with an essentially constant thickness. During its manufacture, the lead frame is initially an elongated structure, only a part of which is shown in FIG. 5. The lead frame is then divided into individual sections, one for each semiconductor housing, along the section lines 52 , 54 . An electronic component is then attached to the lead frame, which is then embedded in the body 10 made of plastic material to form the product shown in FIG. 4.

Fig. 6 shows a modified embodiment in which the terminal pins 12, 14 are replaced by conductive pads 122, 144 which are substantially identical to the terminal pads 16, 18. In this embodiment, control signals would normally be supplied to the underside of the pads 122 , 144 via suitable copper traces on the printed circuit or on the IMS circuit board to which the semiconductor package is attached.

FIG. 7 shows a section of the lead frame which is suitable for the production of such a semiconductor package. Here, too, the cutting lines are denoted by 52 , 54 .

In this embodiment, the connection pads 16 , 18 , 122 , 144 are partially sheared, as can best be seen from FIG. 8. The shearing process is performed at the same time that the lead frame is punched out, and this is achieved through the use of offset die cuts 60 , 62 which work in exactly the same way as scissors. The movement of the die cuts will however, stopped before the terminal pad is sheared or punched through.

It can be seen that this stepped arrangement could also be used for the connection pads 16 , 18 of the embodiment according to FIG. 2.

The advantage of forming a stepped pad in this manner is that the bottom surface of the pad ( 64 in Fig. 8) can be positioned further down from the general plane of the lead frame without the need to remove the lead frame to form a blank with several thicknesses or levels.

Semiconductor packages of the type described can for example a length of approximately 30 mm and a width of approximately 18 mm exhibit. You can transfer power up to 100 watts Process at 40 amps.

Claims (18)

1. Semiconductor housing for surface mounting, with a semiconductor component molded into a body made of plastic material ( 10 ) and a flat conductive heat sink for this purpose, with two input electrodes ( 12 , 14 ) for controlling the semiconductor component and with an output electrode ( 16 , 18 ) for supplying an output signal from the semiconductor component, the input and output electrodes extending from the heat sink fastening, characterized in that the input electrodes ( 12 , 14 ; 122 , 144 ) and the output electrodes ( 16 , 18 ) on opposite ends of the housing are arranged. 2. Semiconductor package according to claim 1, characterized in that the input electrodes ( 12 , 14 ) comprise elongated connecting pins which are bent out of the general plane of the semiconductor package. 3. A semiconductor package according to claim 2, characterized in that the elongated pins ( 12 , 14 ) are directed towards each other inwards, the outer ends of the pins being generally parallel. 4. Semiconductor package according to one of the preceding claims, characterized in that the input electrodes ( 12 , 14 ) and the heat sink attachment are punched out of a blank with a uniform thickness. 5. Semiconductor package for surface mounting, with a semiconductor component molded into a body made of plastic material ( 10 ) and a flat conductive heat sink for this purpose, with two input electrodes ( 12 , 14 ) that extend from the edge of the heat sink mounting to the Control semiconductor device, and with an output electrode ( 16 , 18 ), which extends from the edge of the heatsink mounting and provides an output signal from the semiconductor component, the input and output electrodes extending from the body ( 10 ) , characterized in that the body ( 10 ) has a channel ( 22 , 24 ) in its lower surface, and in that this lower surface is flat and, when using the semiconductor housing, is designed so that it with a mounting substrate ( 33 ) in Touch. 6. A semiconductor package according to claim 5, characterized in that the channel ( 22 , 24 ) extends across the lower surface between the output electrode ( 16 , 18 ) and a further electrode. 7. The semiconductor package according to claim 6, characterized in that the further electrode a second Output electrode forms. 8. A semiconductor housing according to claim 6 or 7, characterized in that the channel ( 22 , 24 ) is formed such that it forms a through channel between the body ( 10 ) of the semiconductor housing and a mounting substrate ( 33 ) when using the semiconductor housing through which washing solutions can be passed. 9. A semiconductor package according to claim 8, characterized in that two spaced apart output electrodes ( 16 , 18 ) are provided and that the channel ( 24 ) has on one side an opening ( 26 ) which opens between the two output electrodes. 10. A semiconductor package according to claim 5, characterized in that the channel ( 22 ) has in one of its sides an opening ( 28 ) which opens between the input electrodes ( 12 , 14 ). 11. Semiconductor housing for surface mounting, with a semiconductor component molded into a body made of plastic material ( 10 ) and a flat conductive heat sink for this purpose, with two input electrodes ( 12 , 14 ) for controlling the component and with an output electrode ( 16 , 18 ) which provides an output signal from the semiconductor device, the input and output electrodes extending out of the body ( 10 ), characterized in that the output electrode is formed by a connection pad ( 16 , 18 ) which is arranged in this way when using the semiconductor package that it is in contact with a conductive portion ( 38 ) of a mounting substrate ( 33 ) and that the terminal pad is deformed in steps by partial shearing. 12. Semiconductor package according to claim 10, characterized in that the input electrodes are also formed by terminal pads ( 122 , 144 ) which are deformed in steps by scissors. 13. The semiconductor package according to claim 12, characterized in that each connection pad from a raw ling is punched out. 14. The semiconductor package according to claim 13, characterized in that the blank is essentially a has only thickness. 15. Semiconductor package for surface mounting, with a semiconductor component formed in a body made of plastic material ( 10 ) and a flat conductive heat sink, with two input electrodes ( 12 , 14 ) for controlling the semiconductor component and with an output electrode ( 16 , 18 ) for supplying an output signal from the semiconductor component, the input and output electrodes extending from the body ( 10 ), characterized in that the input electrodes ( 12 , 14 ; 122 , 144 ) are arranged at one end of the body ( 10 ) while the output electrode ( 16 , 18 ) is located at the opposite end. 16. A semiconductor package according to claim 15, characterized in that the body ( 10 ) is generally quite angled, that the input electrodes ( 12 , 14 ) are arranged adjacent to one of the narrow sides of the body ( 10 ) and that the output electrode ( 16 , 18 ) is arranged adjacent to the opposite narrow side. 17. A semiconductor package according to claim 16, characterized in that the input electrodes ( 12 , 14 ) are signal electrodes and that the output electrode ( 16 , 18 ) is a power electrode. 18. The semiconductor package according to claim 15, characterized in that it is a variety of semiconductors contains components.